This is gonna sound kinda gross- but it had to be done in name of testing. I got three thicknesses of polyester clothing at Walmart. There is a thin stretch material made by athletic works (5.00ea), a slightly thicker polyester zip neck made by starter (3.00ea), and a thick polyester zip neck made by athletic works (11.00ea).
Friday I left for work at 6:00 am wearing the thin layer and the medium layer under a jacket. I was outside until noon. I left work with backpack and headed to the mountains. I changed pants and shoes, added the thicker layer and a Marmot Precip and started hiking. I hiked until 7:30, and it was somewhat strenuous. Temps that night got down to 30 degrees. I slept in the same clothes -sans Precip. I woke up Saturday and hiked all day. I slept in the same clothes again. Sunday I hiked from 9:00 until 2:00 in the same clothes. Nightime temps were 30 degrees and daytime reached 48 degrees. I was from 1800 to 4200 feet above sea level. I thought the stuff performed really well. My body temps were very well regulated through through a wide range of enviromental temps. I did not have to take off and put on clothes as conditions changed and I never felt sweaty. The only thing I added or took away was the wind shell and that was due to temperatures and not excertion. Wind ranged from <2 to >5 mph. No precip. There was no noticable odor retention, no feeling of claminess. I guess basically I was unaware that I had anything on. I also got a pair of athletic works compression shorts. I was afraid of these because I hate that squeezed feeling that you get from bike shorts. These things felt great and there was no chaffing. I guess the best thing I can say about this stuff is that I was unaware that I had anything on and to me that is the best clothing there is. Athletic works is sized big so try it on before you buy it.